The way I understand it----
In general, Aerobatic Flying and 3-D Aerobatics have different characteristics and requirements. Usually, General Aerobatic refers to Pattern and IMAC type of aerobatics, very precision. The requirements here are more toward higher air speed, so higher pitch props are used (10, 12, 14). A 16x10, 16x12, or 16x14 would probably load the OS 1.60 sufficiently and give excellent General Aerobatic air speed and vertical performance. For 3-D type Aerobatics the plane is usually at or close to stall speed, and the requirement is for lots of Static pulling power, and lots of prop generated airflow over the control surfaces. Thus the lower pitch props (4, 6, 8) with higher diameter are generally used.

I don't think the OS 1.60 will pull a 18x10 or higher fast enough, and I think a 16x8 or lower would let the engine destroy itself with high RPM's.